The invention relates to panels for collecting solar energy to effect the heating, by solar radiation, of a liquid circulating in a section of piping and enclosed by a flat rectangular insulated box containing the said section of piping and closed by a cover transparent to solar radiation.
It equally concerns assemblies composed of several such collecting panels justaposed with their respective sections of piping interconnected.
It is known that liquid (generally water, with or without antifreeze) heated by such collecting panels or assemblies is advantageously used for feeding a central heating system and/or a hot water distribution system, especially for household purposes, or again for heating swimming pools, etc.
The invention has as a primary object to render collecting panels of the type in question better adapted to their function and in particular more robust, and easier to fabricate, handle and instal.
It is characterised essentially in that the box of such a collecting panel is constituted by a stamped metal sheet, especially one based on aluminium, whose surface is less than 1 meter sqd.
In the preferred embodiments, attention is directed to one or the other of the following features, considered separately or in combination;
the section of piping contained in the box of a collector being, in intimate contact within this box with a plate of thermally conductive material parallel to the bottom of the box and separated from this bottom by an insulating pad, the said plate constitutes the bottom of a tray less deep than the box, being obtained like the box by stamping and contained within this box,
the section of piping contained in the box of a collector of the type in question being, in intimate contact within this box with a plate of thermally conductive material parallel to the bottom of the box and separated from this bottom by an insulating pad, the said insulating pad is constituted by a rigid block of foam, preferably of polyurethane, moulded directly by injection into the spaced delimited between the box and plate,
the lateral walls of the interior tray are extended towards the exterior by rims parallel to the bottom of this tray and serving to support the transparent cover, preferably with the interposition of an adhesive, the edge of this rim being maintained spaced from the wall of a box, which surrounds this edge, by a space provided with a thermally insulating material,
in a collecting panel of the preceding type, the side walls of the box are extended towards the exterior by flat rims parallel to the bottom of this box and the edges of the internal tray are off-set, relative to these rooms, by a distance d, measured in the direction perpendicular to this bottom, slightly greater than the thickness of the transparent cover,
in a collecting panel of the preceding type, the box presents at each of its four corners a recessed step delimited externally by a flat ledge, of generally triangular or analogous form, off-set by the distance d towards the bottom of the said box relative to the flat peripheral rims of this box so that each of these ledges can serve to support one of the four corners of the transparent cover, preferably with the interposition of an adhesive,
the section of piping of each box is mounted fixedly in a groove formed in the bottom of the tray during the stamping of the latter, this groove being preferably open downwardly in such a manner that the section of piping fits on the lower face of the bottom of the tray,
the positioning of the plate relative to the bottom of the box is determined, before formation of the foam injected in situ, by means of rigid prefabricated spacers in this same foam and by means of the rigid ends of the section of piping, which are themselves fixed on the side walls of the box by means of rigid members of thermally insulating material,
the transparent cover is constituted of cast glass and has an exterior surface of low reflectivity, especially fluted, corrugated, or provided with any other desirable roughness or unevenness,
the collecting panel is prefabricated, with its transparent cover mounted tightly on the box.
The invention includes, apart from these principal features, certain other features which are preferably used at the same time and which are dealt with more specifically below.